This paper explores a neglected aspect of the wider debate about EU
enlargement; namely bilateral disputes between a Member State and an
applicant, where the former uses, or threatens to use, its membership to block
membership to resolve a dispute. As we show through analysis of three cases -
Italy and Slovenia, Slovenia and Croatia, and Greece and Macedonia - the EU’s
transformative power does not always flow ‘outwards’ towards the state seeking
membership. This raises interesting questions about enlargement as
international bargaining between sovereign states filtered via a supranational
entity formally responsible for the negotiations. Our cases suggest limits to
the EU’s transformative power in the context of disputes that are linked to
the meaning and significance of borders. When enlargement intersects with
identity politics, the result can be potentially destabilizing in ways that
can lead to a decline in the EU’s legitimacy. It is not surprising that the
Commission prefers disputes to be resolved bilaterally or via a third-party.